Small Test - History If The Periodic Table Flashcards
1
Q
How is the periodic table arranged
A
- the row of elements is the period; (same shells)
- The column of elements is the group: (they have similar chemical properties, same amount of electrons on outer shell)
2
Q
Which is the atomic and mass number
A
Atomic = smaller
Mass = bigger
3
Q
John Newlands
A
-ordered his table in order of atomic mass
- realised similar properties occurred every 8th element ‘law of octaves’. But it broke down after Calcium
4
Q
Dimitri Mendeleev
A
- ordered in atomic mass, but not always strictly - i.e. in some places he changed that order based on atomic weights
- he left gaps for elements that he thought hadn’t been discovered yet
5
Q
Why’s it called the periodic table
A
Similar properties occur at regular intervals
6
Q
Modern day periodic table
A
- filled in
- knowledge of isotopes helped explain why order of atomic weight is not always correct
- ordered in atomic number
7
Q
What did we first think atoms were
A
- tiny spheres that couldn’t be divided
8
Q
Describe plum pudding model
A
- we discovered electrons
- we thought that the atom was a ball of positive charge negative electrons embedded in it
9
Q
Rutherford’s experiment of alpha particles told us…
A
- some particle were undivieated: Atoms are mostly empty space
- some particles were rebounded: Atoms contain a small and heavy nucleus
- some particles were deflected but still coninued: Atoms Nucleus has a strong positive charge
10
Q
Neil Bhor
A
- suggested electrons orbit the nucleus at specific distances (supported by experimental data)
11
Q
Later experiments
A
- positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge (protons)
12
Q
James Chadwick’s work
A
- provided the evidence to show the existence of neutrons in the nucleus (had been an accepted scientific idea for about 20 years already)
